1. Field of the Invention
This invention relates to antenna sensors and in particular to a millimeter wave and infrared sensor employing a common receiving aperture.
2. Description of the Prior Art
False target acquisitions have degraded the cost effectiveness of single sensor seekers. Weather conditions and the time of day may adversely affect the ability of the sensor to acquire the target. Millimeter wave (MMW) energy is useful under adverse weather conditions. However, the resolution is not as precise as exhibited by optical systems operating in the infrared (IR) region. In an optical system, resolution is adversely affected by rain, fog or humidity. These conditions can reduce the effectiveness of such sensors in the optical spectral region. Target acquisition can be substantially improved by combining millimeter wave and infrared optical signals, substantially reducing the influence of climatic conditions. IR and MMW are also susceptible to known countermeasures of various kinds and therefore a combined aperture system is less susceptible to a single type of countermeasure.